Recent questions in Chemistry

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1 answer 62 views

A student needs to calculate the maximum electrical work that can be obtained from an electrochemical cell of standard hydrogen electrode (SHE) potential -0.76 V and a zinc electrode potential of -0.46 V, when 0.5 moles of zinc metal is oxidized to form zinc ions at 25 °C. Assume that the Faraday constant is 96,485 Coulombs per mole of electrons and the gas constant is 8.314 J/mole.K.

asked Jan 22 in ElectroChemistry by FGHMireya983 (290 points)

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1 answer 68 views

A student needs to calculate the heat of mixing for a 50 mL solution containing 0.1 M HCl and 0.1 M NaOH. The temperature of the solution is 25°C and the density is 1 g/mL. The enthalpy of neutralization for HCl and NaOH is -57.3 kJ/mol. Determine the heat of mixing for the solution.

asked Jan 22 in ThermoChemistry by ConnorHoller (390 points)

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1 answer 67 views

A student needs to calculate the Faraday constant for the reduction of copper ions in a solution using a current of 2.5 amperes for 5 minutes. If the mass of copper deposited on the cathode was 0.3 grams, what is the value of the Faraday constant?

asked Jan 22 in ElectroChemistry by KarlaZaragoz (350 points)

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1 answer 59 views

A student needs to calculate the enthalpy change for a chemical reaction given the enthalpies of formation of the reactants and products. The specific problem is: Calculate the enthalpy change for the reaction:CH4(g) + 2O2(g) → CO2(g) + 2H2O(l)Given the following enthalpies of formation:ΔHf(CH4) = -74.8 kJ/molΔHf(CO2) = -393.5 kJ/molΔHf(H2O) = -285.8 kJ/mol

asked Jan 22 in Chemical reactions by JustinePeter (390 points)

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1 answer 65 views

A student needs to calculate the efficiency of an electrochemical cell that has a potential difference of 1.5 volts and a current of 0.5 amperes passing through it, with the help of Faraday's Law. If the electrode reaction produces chlorine gas with a Faraday efficiency of 79%, and the overall voltage efficiency of the cell is 85%, what is the efficiency of the electrochemical cell?

asked Jan 22 in ElectroChemistry by KristanQ4398 (470 points)

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1 answer 59 views

A student needs to calculate the efficiency of a voltaic cell that has a standard potential difference of 0.78 V and produces a current of 2.5 A. The cell is operated for 8 hours and consumes a total of 2400 Coulombs of charge. What is the efficiency of this electrochemical cell?

asked Jan 22 in ElectroChemistry by DenisNapoli4 (350 points)

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1 answer 108 views

A student needs to calculate the current density (in Amperes per square meter) of a copper electrode (Area = 10 cm²) in an electrochemical cell where the half-cell reaction is Cu²⁺ + 2e⁻ → Cu and the cell voltage is 1.1 V. The concentration of Cu²⁺ in the cell is 0.1 M.

asked Jan 22 in ElectroChemistry by Yolanda3113 (230 points)

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1 answer 55 views

A student needs to calculate the current density (in A/m^2) in an electrochemical cell with a cross-sectional area of 0.01 m^2 and a current of 0.5 A passing through it. The half-cell reactions are as follows:Anode: Zn(s) -> Zn2+(aq) + 2e^-Cathode: Cu2+(aq) + 2e^- -> Cu(s)The concentrations of Zn2+ and Cu2+ ions in the solutions are 0.1 M and 0.01 M, respectively. The temperature of the cell is 298 K. Calculate the current density.

asked Jan 22 in ElectroChemistry by BQDCarmon78 (350 points)

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1 answer 68 views

A student needs to calculate the activation energy for a reaction that takes place at an electrode with a current density of 2.5 mA/cm² at a temperature of 25°C. The reaction has a transfer coefficient of 0.5 and a standard rate constant of 2.0 × 10⁻⁶ cm/s. The student has access to the necessary thermodynamic data for the reaction. What is the activation energy for this electrochemical reaction?

asked Jan 22 in ElectroChemistry by ReganBrady59 (690 points)

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1 answer 76 views

A student needs to analyze an unknown sample to determine the percent composition of three compounds present in it. The student conducts a combustion reaction to determine the percent of carbon and hydrogen in the sample. The remaining residue is then dissolved in water and the solution is titrated with a standardized silver nitrate solution to determine the chloride ion concentration in the sample. Calculate the percent composition of each compound in the unknown sample using mass balance calculations.

asked Jan 22 in Analytical Chemistry by HildredCampo (370 points)

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1 answer 80 views

A student mixed 25.0 grams of sodium hydroxide with excess hydrochloric acid. If the theoretical yield of sodium chloride is 34.0 grams, what is the percent yield of the reaction?

asked Jan 22 in Chemical reactions by IolaEmert895 (410 points)

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1 answer 75 views

A student mixed 10 grams of iron and 15 grams of oxygen to produce iron oxide. What is the limiting reactant and what is the mass of the iron oxide produced? (Assume all reactions are complete)

asked Jan 22 in Chemical reactions by AdolfoCarpen (380 points)

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1 answer 62 views

A student mixed 0.1 M solution of NH3 and 0.1 M solution of NH4Cl to form a buffer solution of NH3/NH4+. If the initial pH of the solution is 9.25, what will be the final pH of the solution when 0.01 moles of HCl is added? (Assume the volume of the solution is constant).

asked Jan 22 in Chemical equilibrium by EleanorNettl (410 points)

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1 answer 86 views

A student measures the current in a galvanic cell with a standard potential of 1.10 V, using a Zinc electrode and a Copper electrode. The student recorded the current as 0.50 A. What is the rate of the electrochemical reaction occurring in the cell?

asked Jan 22 in ElectroChemistry by KatriceFairc (330 points)

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1 answer 59 views

A student is trying to synthesize a compound in the lab. The theoretical yield of the compound is 15 g, but due to some errors during the experiment, the student was only able to obtain 10 g in the end. Calculate the percent yield of the experiment.

asked Jan 22 in Chemical reactions by Malinda52F72 (390 points)

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1 answer 103 views

A student is trying to determine the heat capacity of a substance at constant pressure, given its thermodynamic properties. The substance is in the gas phase and is confined to a container at a specific temperature and pressure. What is the mathematical expression for the heat capacity of the substance in terms of its thermodynamic properties, and what is the numerical value of the heat capacity at the given temperature and pressure? How would the heat capacity change if the temperature or pressure were to be changed?

asked Jan 22 in Physical Chemistry by ChandraMcken (430 points)

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1 answer 82 views

A student is studying the overpotential in an electrochemical reaction in a laboratory experiment. The student measures a current of 2.1 A at an electrode potential of -0.6 V, and 1.95 A at -0.5 V. What is the overpotential of the reaction?

asked Jan 22 in ElectroChemistry by Barrett98Q2 (270 points)

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1 answer 83 views

A student is studying the kinetics of a reaction between hydrogen and iodine gases. They measure the initial rate of the reaction to be 0.025 mol L^-1 s^-1 at a particular temperature. They want to calculate the rate constant for this reaction using this information. What is the rate constant of this reaction at this temperature?

asked Jan 22 in Chemical kinetics by JesseEarnhar (130 points)

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1 answer 85 views

A student is studying the electrochemical reaction of the metal copper in acidic solution. They measure the current density at different applied potentials and obtain the following data:Potential vs. SHE (V) | Current Density (mA/cm²)---|---0.0 | 0.00.1 | 0.50.2 | 2.00.3 | 5.00.4 | 11.0Using this data, calculate the anodic and cathodic Tafel slopes, and determine the rate constant for the electrochemical reaction.

asked Jan 22 in ElectroChemistry by JulianSikora (430 points)

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1 answer 66 views

A student is studying the electrochemical behavior of a certain metal ion in a solution of varying pH values. They have measured the anodic and cathodic Tafel slopes for the electrode reaction at each pH. The anodic Tafel slope values range from 60 mV/decade to 90 mV/decade, and the corresponding cathodic Tafel slope values range from 50 mV/decade to 70 mV/decade. Is this metal ion undergoing a one-electron or a two-electron transfer reaction? Justify your answer.

asked Jan 22 in ElectroChemistry by LoriSelwyn3 (370 points)

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